As a planetary gear including a carrier that rotatably supports short pinions and long pinions that mesh with the short pinions, there has hitherto been known a planetary gear including a middle member having a base plate portion that supports respective first ends of pinion shafts of the short pinions, a one-side member having a bottom plate portion and a peripheral edge portion that integrally extends toward one side in the axial direction from the periphery of the bottom plate portion and disposed on one side of the base plate portion of the middle member in the axial direction so that the bottom plate portion supports respective first ends of pinion shafts of the long pinions, and an other-side member having a bottom plate portion and a peripheral edge portion that integrally extends toward the other side in the axial direction from the periphery of the bottom plate portion and disposed on the other side of the base plate portion of the middle member in the axial direction so that the bottom plate portion supports respective second ends of the pinion shafts of the short pinions and respective second ends of the pinion shafts of the long pinions (see Patent Document 1, for example). In the planetary gear, a frame body that supports the short pinion and the long pinion is structured by securing the peripheral edge portion of the one-side member and the peripheral edge portion of the other-side member to respective sides of the base plate portion of the middle member in the axial direction. That is, the distal end of the peripheral edge portion of the one-side member is inserted into a long hole formed in the base plate portion of the middle member, and welded to the base plate portion. Meanwhile, the distal end of the peripheral edge portion of the other-side member is welded to a connection portion formed on the base plate portion of the middle member to be positioned on the outer peripheral side of the long hole.